This isn’t new territory for Sergio Pettis. He’s certainly been down this road before and come through it just fine on the other end.

On Friday night, Pettis (7-0) meets Dillard Pegg (5-1) for Resurrection Fighting Alliance’s inaugural flyweight title. But he meets Pegg on short notice when his original opponent, Jeff Curran, pulled out of the fight.

RFA 8 takes place at The Rave in Milwaukee. The main card, including the Pettis-Pegg main event, airs live on AXS TV (10 p.m. ET).

“This happened to me a few months ago – Matt Manzanares hurt his knee two weeks before the fight, and they didn’t have any opponent,” Pettis told MMAjunkie.com Radio (www.mmajunkie.com/radio) of a planned fight at April’s RFA 7 event. “It’s really frustrating – you’re cutting weight, training really hard, and they switch opponents on you like that.”

But Pettis said a lot of what he was doing to prepare for MMA veteran Curran – who has fought for titles in the WEC and is a UFC, Strikeforce and Bellator vet, as well – carried over to Pegg, who has just six pro fights as opposed to Curran’s 50.

“It sucks, but the camp was kind of the same – takedown defense and working the striking,” Pettis said.

One thing that might have been a little different for him this time around, though, was the weight cut. Pettis, just 19 and the younger brother of UFC lightweight Anthony, said he bulked up after his most recent fight, a unanimous decision win over Josh Robinson in March.

A light heavyweight or middleweight needing to drop 33 pounds is common in MMA. But a flyweight?

“I had a lot of weight to cut this time,” he said. “I got really fat after my last fight – I had three weeks off and I just ate as much as possible, so I got up to 158 and had to lose 33 pounds for this fight. I had two months, but I also went to Brazil during my camp, so it wasn’t the cleanest diet for the first two weeks.”

It also made Pettis realize he might need to start thinking about fighting a weight class up.

“I don’t know how much I’m going to grow,” he said. “I’m only 19, and maybe my body’s going to grow – hopefully. I don’t know how long the ’25 cut is going to be. It’s starting to get harder and harder. Maybe I need to just not eat as much when I’m off training camps. Cutting weight sucks in general, but I make it through it pretty well and my body recovers pretty fast.”

Pettis will have a home fight against Pegg. He grew up in Milwaukee alongside Anthony, and the two quickly have become one of the most successful brother combos in the sport’s history – with plenty of time to go, and before Sergio even gets to the UFC, which most experts say is just a matter of time.

With three decisions in his past four fights after starting his pro career with three stoppages, Pettis may be looking to get back to a finish against Pegg, who will make the trip to Milwaukee from Ohio.

But he also is planning for a motivated opponent, not one who is coming in to just get a paycheck. There’s a title on the line, after all, and a win over one of the most touted young fighters in the sport would boost Pegg’s stock a ton.

“He’s going to come forward,” Pettis said. “I respect him a lot – he took this fight on short notice. I like to think of myself as a tough opponent. He has nothing to lose for this fight. This is his biggest opportunity, and he’s going to try to finish me.

“But I’m not going to let that happen. I’m too smart for that, and I trained way too hard for this fight.”

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